The valve bracket production process is mainly divided into a cast valve bracket and a forged valve bracket. The cast valve bracket is the valve bracket formed by casting. Generally, the pressure of the cast valve is relatively low (such as PN16, PN25, PN40, but also high pressure, it can reach 1500Lb, 2500Lb), most of the caliber is more than DN50. Forged valve brackets are forged, and are generally used on high-grade pipelines. The caliber is relatively small, generally below DN50.
Valve bracket casting method
1. Casting: It is the process of smelting metal into a liquid that meets certain requirements and pouring it into a mold, and then cooling, solidifying and clearing to obtain a casting (part or blank) having a predetermined shape, size and performance. The basic process of the modern machinery manufacturing industry.
2. The blank produced by casting has low cost, and it can show its economicality for parts with complicated shape, especially with complex internal cavity; at the same time, it has wide adaptability and good comprehensive mechanical properties.
3, but the materials required for casting production (such as metal, wood, fuel, modeling materials, etc.) and equipment (such as metallurgical furnace, sand mixer, molding machine, core machine, falling sand machine, shot blasting machine, cast iron plate, etc. There are many, and it will produce dust, harmful gases and noise and pollute the environment.
4. Casting is a metal thermal processing technology mastered by humans. It has a history of about 6,000 years. In 3200 BC, copper frog castings appeared in Mesopotamia. Between 13 BC and the 10th century BC, China has entered the heyday of bronze castings, and its craftsmanship has reached a fairly high level, such as the Shang dynasty’s 875 kilograms of the mother Wu Fangding, the Warring States’ Zeng Houyi and the Western Han Dynasty. The light-transparent mirrors are all representative products of ancient casting. The early casting was greatly influenced by pottery, and most of the castings were tools or utensils for agricultural production, religion, and life, and the artistic color was strong. In 513 BC, China cast the world’s first iron castings found in the text – Jin Guozhu Ding (about 270 kg weight). Around the 8th century AD, Europe began to produce cast iron parts. After the industrial revolution of the 18th century, castings entered a new era of service for large industries. In the 20th century, the development speed of casting was very fast. The development of spheroidal graphite cast iron, malleable cast iron, ultra-low carbon stainless steel and aluminum-copper, aluminum-silicon, aluminum-magnesium alloy, titanium-based, nickel-based alloy and other cast metal materials was developed. A new process for the inoculation of cast iron. After the 1950s, there were new technologies such as wet sand high pressure molding, chemical hardening sand molding and core making, negative pressure molding, and other special casting and shot blasting.
5. There are many kinds of castings. According to the modeling method, it is customarily divided into:
(1)Ordinary sand casting, including wet sand type, dry sand type and chemical hardening sand type.
(2)Special casting, according to the modeling material, can be divided into special castings with natural mineral sandstone as the main modeling material (such as investment casting, clay casting, casting workshop shell casting, negative pressure casting, solid casting, ceramic casting). Etc.) and special castings with metal as the main casting material (such as metal casting, pressure casting, continuous casting, low pressure casting, centrifugal casting, etc.).
6. The casting process usually includes:
(1)The mold (the container that makes the liquid metal into a solid casting) is prepared. The mold can be divided into sand type, metal type, ceramic type, mud type, graphite type, etc. according to the materials used. It can be divided into disposable type and semi-permanent according to the number of times of use. Type and permanent type, the pros and cons of casting preparation are the main factors affecting the quality of castings;
(2)Melting and casting of cast metal. Casting metal (casting alloy) mainly consists of cast iron, cast steel and cast non-ferrous alloy;
(3)casting processing and inspection, casting processing includes removal of core and casting surface foreign bodies, refining risers, burrs and burrs and other projections and heat treatment, shaping, anti-rust treatment and roughing.
Valve bracket forging method
1. Forging: It is a processing method that applies pressure to a metal blank by using a forging machine to cause plastic deformation to obtain a forging having certain mechanical properties, a certain shape and size.
2. One of the two major components of forging. By forging, it can eliminate the looseness of the as-cast state of the metal, weld the hole, and the mechanical properties of the forging are generally superior to those of the same material. For important parts with high load and severe working conditions in machinery, forgings are often used except for the available rolled sheets, profiles or welded parts.
3. forging according to the forming method can be divided into:
(1)Open forging (free forging), using impact force or pressure to deform the metal between the upper and lower two irons (anvil) to obtain the required forgings, mainly hand forging and mechanical forging.
(2)Closed mode forging, metal blanks are pressed and deformed in a forging die with a certain shape to obtain forgings, which can be divided into die forging, cold heading, rotary forging, extrusion and the like. Forging at deformation temperature can be further divided into hot forging (processing temperature is higher than recrystallization temperature of billet metal), warm forging (below recrystallization temperature) and cold forging (normal temperature).
(3)Forging materials are mainly carbon steel and alloy steel of various compositions, followed by aluminum, magnesium, titanium, copper and the like and alloys thereof. The original state of the material is bar, ingot, metal powder and liquid metal. The ratio of the cross-sectional area of the metal before deformation to the area of the die after deformation is called the forging ratio. Proper selection of forging ratios has a lot to do with improving product quality and reducing costs.
